[Go Horns!]

Just got done finishing installing my stereo upgrade. I am using an RTA app on my iPad, and I have a 5 decibel hole at 250 Hz. Here is what I have:

Hifi Stereo
Technic Harness
Arc Audio 1200.6
Jehnert Flatline kit - tweeter, mids, and woofers (http://www.jehnert.de/en/shop/doorbo...-3-5-7-series/)
JL 10-W3v3-4 ohm in a magic box

I installed the amp and subwoofer first. Sounded good, but the factory tweeters were meh.

Did the doors next. Had the sub low-passed at 80 Hz. Had the factory woofers going from 80-200Hz, and the Jenhert mids high-passed at 200Hz. Did an RTA, and had a hole at 250Hz. It still sounded a lot better and had a lot more punch. If I did not have the Jehnert woofers, I would have been happy to stop here.

Got the Jehnert Woofers installed this afternoon. I first had to switch the positive and negative at the amp for the woofers. Forgot about the whole stock woofers out of phase thing. I connected the Jehnert positive to the positive lead on the pigtail, and that ended up with very low output for the low-mid-range sound. Instead of taking the floor apart again, I just switched the polarity at the amp. Got the low-mids back.

I was hoping that I could play the woofers up higher to get rid of the 250Hz hole. So I set the cross-overs at the following: the sub low-passed at 70, woofer from 70-300, and doors high-passed at 200. But still had a hole at 250Hz.

So I figure that it is at least one of three things:
1. Because of the acoustics of the car, it is always going to have the hole without DSP.
2. The Jehnert door crossover bandpasses the mid-range or it just can't get down to 250Hz and the Jehnert woofer cannot get up to 250Hz. (least likely, but possible)
3. I need to get a real RTA because the iPad microphone sucks.

It is probably the acoustics, which I'm fine with. But wanted to know if anyone else had this happen.

[soulgod123]

at had a "mountain" with prof HU at 200+hz and completely had to mess arround with eq, couldnt stand with this, changed to aftermarket and all gone

View post on imgur.com

[Shotputted]

Do you hear the hole while listening to music or is it a perfectionist kind of thing? I have different speakers but I LP my woofers at 250, the same hz for the HP of my mids. It sounded off at first but eventually I increased the gain on the woofer channel some more and have the bass eq in the HU at 0 and I'm really happy with it. My speakers just needed a boost to hit those higher notes.

Also could you explain more about the out of phase woofers? Should I consider flipping the polarity of the woofers?

[ctuna]

There is a physical limitation with 4 inch speakers. (They don't
go that low)
That being said some are better than others with Morels being
the ones that are speced to play the lowest . And for underseats
you can bridge the gap some with Jehnerts.
I am guessing that a dsp might be the best bet though.

[kaigoss69]

You generally don't want the underseats playing higher than 150Hz, so try to cross over in that range and use a steep slope if possible. That may or may not fix the hole. You need a DSP to get a decent frequency response.

[taibanl]

Originally Posted by kaigoss69

You generally don't want the underseats playing higher than 150Hz, so try to cross over in that range and use a steep slope if possible. That may or may not fix the hole. You need a DSP to get a decent frequency response.

I would caveat that:

1) it depends on your midrange and midbass driver

2) Andy W's IASCA winning tune from Biggs BMW was crossed at 200hz

Its a tradeoff between upfront imaging and frequency response. So, as always YMMV.

[Go Horns!]

I don't necessarily hear the gap. And our brains are better about filling gaps than they are about dealing with peaks (and my diff whine at 900 hz reminds me of that every time (going to be the subject of another post)). I also used a different RTA app and microphone this past weekend, and it showed less of a hole at 250Hz. Did some fine tuning with the basic settings on the HU to get to an enjoyable sound. But it was mostly a perfectionist thing.

I used the Jehnert mids and tweeters because I was able to get the whole set used. If I was buying new, I would use the Morel Hybrid 402 slim. Or the JL C5-400 mid with a morel tweeter. May eventually go that way. But for now I'm happy. Plus I used the saved $500 to buy a rearview camera retrofit.

When I say that I have the underseats out of phase, I am talking about switching the polarity. But I think I had to switch the polarity to get them in phase. It is my understanding that the stock woofers are inverted, so they need to be played out of phase. So when you put an aftermarket woofer in, you need to switch the polarity. Best way to determine if you should or should not switch them is to RTA and see what gives you the higher level. But I could tell right away that something did not sound right.

Sounds like I need to save for a DSP. My problem is that I live in the Apple universe, and most DSPs require a Windows machine. Waiting to see if AudioControl lives up to its promise of having Apple compatible software.

[kaigoss69]

Originally Posted by taibanl

I would caveat that:

1) it depends on your midrange and midbass driver

2) Andy W's IASCA winning tune from Biggs BMW was crossed at 200hz

Its a tradeoff between upfront imaging and frequency response. So, as always YMMV.

True, but Biggs was using the stock mids so they had to cross over that high, and they got away with it. Could it have been even better, sure!

[Ali-E90]

Not to hijack the thread, but I have a similar situation. Haven't used an app to confirm (is there a free iOS app?), but I too hear a whole, and I'd guess it's in the 200+ range also.

I have a 3-way audio system x200 set (made for e90), and a sub in the boot (so my under seat woofers don't need to play too either)

I've tweaked the crossover (amp & HU) and HU eq (pioneer avic) but still not "right".

Any thoughts or suggestions would be welcome.

[Go Horns!]

Free RTA App: https://itunes.apple.com/us/app/rta-...525324684?mt=8

[SteveEvans]

I had a dip in response between 160 and 200Hz, but I had my crossover frequency at 160Hz. I needed to adjust the phase on the mids to fix it.

Steve

[Ali-E90]

Originally Posted by SteveEvans

I had a dip in response between 160 and 200Hz, but I had my crossover frequency at 160Hz. I needed to adjust the phase on the mids to fix it.

Steve

What do you mean adjust the phase of the mids? Change the polarity?

Wouldn't a crossover adjustment make more sense? Maybe change the hpf slope for the mids?

[p-lethal]

Originally Posted by Go Horns!

I don't necessarily hear the gap. And our brains are better about filling gaps than they are about dealing with peaks (and my diff whine at 900 hz reminds me of that every time (going to be the subject of another post)). I also used a different RTA app and microphone this past weekend, and it showed less of a hole at 250Hz. Did some fine tuning with the basic settings on the HU to get to an enjoyable sound. But it was mostly a perfectionist thing.

I used the Jehnert mids and tweeters because I was able to get the whole set used. If I was buying new, I would use the Morel Hybrid 402 slim. Or the JL C5-400 mid with a morel tweeter. May eventually go that way. But for now I'm happy. Plus I used the saved $500 to buy a rearview camera retrofit.

When I say that I have the underseats out of phase, I am talking about switching the polarity. But I think I had to switch the polarity to get them in phase. It is my understanding that the stock woofers are inverted, so they need to be played out of phase. So when you put an aftermarket woofer in, you need to switch the polarity. Best way to determine if you should or should not switch them is to RTA and see what gives you the higher level. But I could tell right away that something did not sound right.

Sounds like I need to save for a DSP. My problem is that I live in the Apple universe, and most DSPs require a Windows machine. Waiting to see if AudioControl lives up to its promise of having Apple compatible software.

did you need to change the polarity on both woofers to bring them in phase or just one? i wonder if this is why i am currently unimpressed with my Jehnerts

[Go Horns!]

I changed the polarity on both woofers. I saw your DSP thread, I'm guessing that the Helix can do phase adjustments on a channel basis, so might as well do it there. Will give you an easy way to do an A/B comparison.

[p-lethal]

Originally Posted by Go Horns!

I changed the polarity on both woofers. I saw your DSP thread, I'm guessing that the Helix can do phase adjustments on a channel basis, so might as well do it there. Will give you an easy way to do an A/B comparison.

yes it does. will give it a shot! thanks!

[OveN]

Originally Posted by p-lethal

yes it does. will give it a shot! thanks!

Note: Swapping polarity on a speaker is not the same as doing a 180 degree phase shift og the signal to that speaker in the DSP. Shifting the phase in the DSP means you are delaying the signal.

[Kalium]

Try putting on a 250Hz signal through a tone generator. Move your head around the car. If it's quiet everywhere in the car then it's not a problem of acoustics.